Doping effect of CrO₃ on crystallization and dielectric behavior of strontium titanate borosilicate glass ceramics

Various compositions of strontium titanate borosilicate glasses doped with CrO₃ were synthesized by using conventional melt quench techniques. The synthesized parent glasses were devitrified on the basis of the results of differential thermal analysis. The differential thermal analysis were recorded from room temperature to 1000 °C with heating rate of 5 °C/min and shows the endothermic peaks. X-ray diffraction studies showed the amorphous nature of the glass samples and their devitrified glass ceramics shows cubic crystal structures. Scanning electron microscopic results confirm the fine and uniform grains distribution of SrTiO₃/Sr₂B₂O₅ as major phase in the glassy matrix. Relative dielectric constant ε_r was measured with variation of temperature at different frequencies. The maximum value of ε_r was found to be 9559 along with dissipation factor, D, 4.85 × 10⁻⁶ at 100 Hz and 673 °C for glass ceramic sample 54[SrTiO₃]–39[2SiO₂B₂O₃]–7CrO₃ crystallized at 756 °C for 3 h. This high value of ε_r is attributed to space charge polarization which arises due to semiconducting nature of crystalline phase of SrTiO₃. Therefore, inclusion of CrO₃ enhanced the crystallites growth during the devitrification of the glass and reduced the dissipation factor.